Bisdorff A R, Bronstein A M, Gresty M A
MRC Human Movement and Balance Unit, National Hospital for Neurology and Neurosurgery, London, UK.
Electroencephalogr Clin Neurophysiol. 1994 Dec;93(6):409-16. doi: 10.1016/0168-5597(94)90146-5.
EMG responses elicited by sudden onset of free fall and a startling auditory stimulus were investigated in healthy subjects while lying on a couch with their eyes closed. Muscle responses were recorded from masseter (V cranial nerve), orbicularis oculi and mentalis (VII nerve) and sternomastoid and trapezoid (XI nerve). A similar sequence of muscle activation and absolute latencies occurred in response to both stimulus modalities, consisting of a blink (30 msec) followed simultaneously by mentalis, sternomastoid and trapezoid (55 msec). Masseter could either be simultaneously activated with the latter muscles or follow after a delay of 10-20 msec. A patient with bilateral cochleo-vestibular nerve section had responses at comparable latencies in the free fall experiment. The similarities between the reaction to free fall and a startling auditory stimulus indicate that the early response to free fall constitutes a startle and that various stimuli converge onto a common response generator. The latency pattern of neck and facial muscles does not follow a sequence of innervation with increasing segmental distance from a single centre. Therefore, our data do not support the concept that the startle response is produced by a caudally and rostrally spreading volley from a putative pontomedullary centre. It is suggested that the startle response is a polysynaptically generated patterned muscle activation.
在健康受试者闭眼躺在长沙发上时，研究了自由落体突然开始和令人惊吓的听觉刺激引发的肌电图反应。从咬肌（三叉神经V）、眼轮匝肌和颏肌（面神经VII）以及胸锁乳突肌和斜方肌（副神经XI）记录肌肉反应。对两种刺激方式的反应中，出现了相似的肌肉激活顺序和绝对潜伏期，包括眨眼（30毫秒），同时颏肌、胸锁乳突肌和斜方肌也会激活（55毫秒）。咬肌可能与后一组肌肉同时激活，也可能延迟10 - 20毫秒后激活。一位双侧耳蜗 - 前庭神经切断的患者在自由落体实验中具有类似的潜伏期反应。自由落体反应和令人惊吓的听觉刺激之间的相似性表明，对自由落体的早期反应构成了惊吓反应，并且各种刺激汇聚到一个共同的反应发生器上。颈部和面部肌肉的潜伏期模式并不遵循从单个中心起节段距离增加的神经支配顺序。因此，我们的数据不支持惊吓反应是由假定的脑桥延髓中心向尾侧和头侧传播的冲动产生的这一概念。有人提出，惊吓反应是一种多突触产生的模式化肌肉激活。
